Cost is partly the issue; after the motor upgrade and I'm ready for a new cartridge it'll be upwards of £200 to get the working properly which is almost as much as the Project. But as danb says the rega tonearm does sound great.
Time to track down the Project for a demo I reckon
I use a Project Debut Carbon for hi-fi duties and can't fault it.
I think they still do the package with the Ortofon Red cart which is ace and there's plenty of upgrades available if you're feeling fancy.
I was on a budget when I bought mine but managed to get a great deal on an ex-demo one.